Objective Rare earth is not only important natural non-renewable resources, but also a key strategic resource. Based on the field geological survey and indoor comprehensive study of sedimentary rare earth resources in the eastern Yunnan and western Guizhou area, this paper reveals the advantages and development and utilization potential of the rare earth resources, which not only enriches the industrial types of the global rare earth resources, but also supports the national strategic reserve of key rare earth resources.

Methods Based on the research on the characteristics of ore-bearing strata, typical ore characteristics, the partition characteristics of rare earth elements and the potential of rare earth resources, this paper discusses the genetic types of the rare earth resources, the occurrence state of rare earth elements and the potential of development and utilization.

Results The ore-bearing stratum is identified as Xuanwei Formation of Upper Permian (P₃x); the lithology of rare-earth rich ore is gray- white aluminite claystone and silty claystone; the origin of rare earth ore belongs to sedimentary type; in Weining County Heishitou—Mazha—Zhejue area, the thickness of ore body varies from 2m to 18m, the ore body extension is relatively continuous, the content of rare earth oxide (TREO) is up to 1.6%, the weighted average grade of ore body block (TREO) is 0.18% to 0.46%, and the inferred resource is over 300, 000 tons; the proportion of "Critical rare earth elements (CREE)" in the rare earth resources is up to 22.6% (∑CREO), which is higher than most of the rare earth deposits under development and utilization at domestic and overseas. In addition, the new selective leaching technology is used in the dressing and metallurgy test, and the results indicate that the recovery of rare earth can reach more than 90%. This new type of rare earth mine is expected to realize large-scale industrial utilization.

Conclusions The sedimentary rare earth resource has the advantages of large ore thickness, high ore grade, large resource potential, low mining cost, high proportion of critical rare earth elements (CREO) in ore, and good development and utilization prospect.